1. Technical Field
The present disclosure relates to an image sensor, and more particularly to an image sensor having a nanodot.
2. Discussion of the Related Art
A color image sensor is a photoelectric transducer that converts light into an electric signal. A conventional image sensor includes a plurality of unit pixels arranged in an array on a semiconductor substrate. Each unit pixel includes a photodiode and a plurality of transistors. The photodiode generates and stores photocharges by receiving external light, and the transistors output electrical signals according to the generated photocharges.
A complimentary metal oxide semiconductor (CMOS) image sensor includes a photodiode that receives and stores an optical signal, and a control device that controls or processes the optical signal to display an image. The control device can be formed using a CMOS forming method. Thus, the CMOS image sensor can be formed in a single chip together with various signal processing devices including the control device.
A unit pixel of the CMOS image sensor can be formed in a sub-micron size. Also, a plurality of pixels can be formed in sub-micron size image sensors. A conventional single sub-pixel region requires a first region for mounting conventional transistors for sending an intensity of light incident to the single sub-pixel region as a single analogue information and a second region for mounting a single analogue digital converter in a single column line.
A micro lens focuses light onto a photoelectric conversion region. However, focusing light onto a photoelectric conversion region using the micro lens is difficult when the photoelectric conversion region is sub-micron size.